A federal grand jury indicted Mariia Butina on Tuesday on charges of conspiracy and acting as a foreign agent, adding a new charge against the Russian national, who was arrested over the weekend in Washington and accused of playing a part in a secret Russian attempt to influence U.S. politics.

The indictments accuse Butina of: cozying up to GOP politicians, the RNC, and the NRA, and attempting to influence them and to connect them with members of the...